01 - Preheat oven to 400°F. Lightly grease a baking dish or ovenproof skillet with olive oil.
02 - In a mixing bowl, combine chopped spinach, softened cream cheese, shredded mozzarella, grated Parmesan, chopped sun-dried tomatoes, minced garlic, ¼ teaspoon salt, and ¼ teaspoon black pepper. Stir until evenly blended.
03 - Using a sharp knife, slice a deep pocket into the side of each chicken breast, taking care not to cut all the way through.
04 - Fill each pocket generously with the spinach-cheese mixture. Secure the openings with toothpicks if needed to keep the filling enclosed.
05 - In a small bowl, mix Italian seasoning, paprika, ½ teaspoon salt, and ¼ teaspoon black pepper. Rub the seasoning blend evenly over all sides of each stuffed breast.
06 - Heat 1 tablespoon olive oil in a large ovenproof skillet over medium-high heat. Sear the stuffed chicken breasts for 2 to 3 minutes per side until a golden crust forms.
07 - Drizzle the remaining 1 tablespoon olive oil over the chicken. Transfer the skillet to the oven and bake for 20 to 25 minutes, or until the internal temperature reaches 165°F.
08 - Remove from the oven and discard any toothpicks. Let the chicken rest for 3 to 5 minutes before slicing and serving.